POS1396 PSORIASIS, WITHOUT RHEUMATOLOGICAL MANIFESTATIONS, IS ASSOCIATED WITH STRUCTURAL CHANGES OF THE SACROILIAC JOINT, A CONTROLLED STUDY USING CT SCAN
Authors: T. Leriche, O. Fakih, F. Aubin, M. Chouk, C. Prati, D. Wendling, F. Verhoeven
Journal: Annals of the Rheumatic Diseases (2022)

Background Plaque Psoriasis (PsO) is an inflammatory disorder that could be associated with rheumatological manifestations defining Psoriatic arthritis. Moreover, recent studies showed that the presence of plaque psoriasis is associated with more structural damage In axial Spondyloarthritis [1]. To our knowledge, no study has specifically evaluated the extent of structural lesions of the sacroiliac joints (SIJs) on computed tomography (CT) in patients with PsO, without rheumatological manifestations, compared with healthy controls. Objectives To describe SIJ CT characteristics in patients with PsO and compare them with those of age- and sex- matched controls. Methods An observational, retrospective study was performed using medical records from Besançon University Hospital’s rheumatology and dermatology departments, which were screened to identify patients with PsO, diagnosed by a dermatologist. A search was then carried out for patients in the hospitals’ imaging archiving system to identify those who had undergone a CT which included the SIJs in their entirety. Non-inclusion criteria were the existence of pelvic bone lesions and a history of pelvic radiotherapy. Each patient was then matched with a control of the same age and sex, recruited through the hospital’s imaging archiving system. For each individual, CT was interpreted by two independent readers using a score previously used by Diekhoff et al. [2], dividing each SIJ into 12 regions, for each of which joint space narrowing (JSN), erosions, and sclerosis are assessed. For this study, we also observed the existence of intra-articular gas and diffuse idiopathic skeletal hyperostosis (DISH) lesions for each region. Quantitative variables were compared using Student’s t-test. Qualitative variables were compared using the Chi-2 test. Results 60 patients and 457controls were included. Mean (SD) age was 52,2 ± 17,7 in the PsO group and 53,6 ± 16.7 in the control group. 31 (52%) were male in PsO group and 30 (54%) in the control group. In the PsO group, BMI was 27,7± 6 versus 26,9 ± 6,44 in control group (p= 0.55). There is a trend for more frequent active smoking in PsO (69% in PsO group versus 54% in control group; p=0.075). In PsO patients, mean disease duration was 20.2 ± 17,6 years, the skin area affected was 41,8% ± 22,6 and the mean number of bDMARDs used was 2.25 (± 1.16). The global SIJ score was higher in the PsO group (6,63 ± 10,7) in comparison with the control group (2,84 ± 4,87). Erosion and sclerosis scores were similar in both group but joint space narrowing score was significantly higher in the PsO group (0.873 (±4.62) versus 4.15 (±10.8); p =0.035). There were no correlations between the global score and the disease duration (Pearson score 0.166 (-0.131; 0.435)) and the severity of the psoriasis (Pearson 0.00937 (-0.259; 0.276)).The number of gestation, active smoking, alcohol intake and physical work have no impact on the global Score. Conclusion The CT characteristics of SIJs from patients with Pso were different to those of age- and sex-matched controls essentially secondary to joint space narrowing. References [1]Lorenzin M, Ortolan A, Vio S, Cozzi G, Scapin V, De Conti G, Doria A, Ramonda R. Psoriasis and Imaging Progression in early Axial Spondyloarthritis: Results from a 48-month follow-up (Italian arm of SPACE study). Rheumatology (Oxford). 2021 Oct 4:keab728. Table 1. CT scan findings between PsO patients and matched controls Controls PsO Erosion 0.42 (±0.91) 0.2 (±0.48) 0.18 Joint space narrowing 0.873 (±4.62) 4.15 (±10.8) 0.035 Sclerosis 1.76 (±2.07) 2.17 (±2.73) 0.37 Global score 2.84 (±4.87) 6.63 (±10.7) 0.015 Gas 34 (62%) 34 (57%) 0.57 DISH 11 (20%) 9 (15%) 0.48 Disclosure of Interests None declared